Means for the mounting of the cutting or grinding ribs or teeth in mills of any type



Feb. 14, 1939. O KRISTOFFERSEN 2,147,167

MEANS FOR THE MOUNTIN F THE CUTTING OR GRINDING RIBS 0R TEETH M ANY TYPE 7 3 Sheets-Sheet l ILLS Filed Jan. '7,

Feb. 14, 1939. o K s o g 2,147,167

' MEANS FOR THE MOUNTING OF THE CUTTING OR GRINDING RIBS OR TEETH IN MILLS OF ANY TYPE Filed Jan. 7. 1937 3 Sheets-Sheet 2 o, KRISTOFFERSEN 2,147,167 MEANS FOR THE MOUNTING OF THE CUTTING OR GRINDING Feb. 14, 1939.

RIBS OR TEETH IN MILLS OF ANY TYPE Filed Jan. 7, 1937 3 Sheets-Sheet 3 Ola} Kms'roFFERsEN INVENTOE, '1 W Patented Feb. 14, 1939 PATENT OfFFl-CE MEANS FOR. THE MOUNTING 'OF THE CUT- TING OR -GRINDING RIBS OR TEETH IN MILLS OF ANY TYPE Olaf Kristoflrersen, Oslo, Norway Application January '7, 1937, Serial No. 119,393 In Sweden September27, 1935 1 Claim.

The present invention relates to mills of any type which are adapted for grinding fibrous material, for instance of vegetable nature, in order to separate the individual fibres or for grinding other materials, for instance minerals etc. and preferably of that type where a rotor element in the form of a cylinder is mounted in a hollow drum or frame structure, both of these members being provided with ribs or teeth which are adapted to comb each other and come into gliding contact with each other in such a way that material which is introduced into the hollow drum will be subjected to a grinding and a tearaction, respectively, between the individual teeth. A mill of this type is for instance described in U. S. A. Patent No. 2,039,807.

One object of the present invention is to provide a spring mechanism between some of the individual ribs or teeth or groups of teeth in the mill of the type above described in order to give the teeth the ability to adjust themselves to the material passing between any two ribs without reducing the grinding action of the remaining ribs or groups of ribs. In mills of this type it necessary to take into consideration that the material to be worked has much larger dimensions at the point where it is fed into the mill than at the outlet end of same. At the same time the material at the feeding end-of the machine is of uneven character, i. e. larger lumps will be mixed with smaller lumps, and for this purpose it is commonly known to use spring means to make it possible for the ribs to adapt themselves to move away from each other, if a piece of material of large dimensions happensto come in between two teeth.

It has previously been suggested, as for instance will appear from the above mentioned patent, to provide each rib with a springy tail in order to make it possible that the rib shall be able to adjust itselfwith reference to that material which at any time will be situated between two ribs, and there have also beenproposed constructions of mills of this type where one of the working parts, for instance the rotor as a whole mounted for spring movements in the axial ction, so that the complete rotor may move within certain limits to adjust the distance between the ribs in accordance with the dimensions of the material to be ground.

The first mentioned arrangement is in many cases ideal, but for some types of work it has proved that it will not work satisfactorily, the last mentioned arrangement has that very obvious drawback that all the ribs simultaneously will be parted from each other, if a larger piece of material happens to come in between two ribs. of causing the machine to work unsatisfactorily with the exception of that pair of ribs between which the large piece of material happens to be.

One object ofthe present invention is to provide in the mill of the type above mentioned an arrangement of ribs which aremounted in such a way that the individual ribs or groups of ribs, at least a substantial number of the ribs mounted in one of the machine parts, for instance in the'drum structure or on the cylinder, are mounted in such a way that they can move individually independent of the other ribs, or groupwise, or both individually and groupwise in relation to each other and in relation to other groups within certain given limits.

According-to this invention, this is made possible by mounting the ribs slidably in the axial direction of the machine and introducing between the ribs spring members, for instance coil springs which will tend to prevent-this movement. By so'doing, one will obtain'the ideal condition, viz. that each rib will work individually, not being effected by the type of material which at any time happens to be between the-remaining ribs.

For grinding some kinds of material, however, it is not necessary to arrange all the ribs for individual movements with reference to all the other ribs, but it is sufficient to arrange larger or small groups of ribs in such a way that they groupwise may adjust themselves with reference to the other teeth or groups of teeth or ribs in the machine.

A further object of the invention is therefore to provide means for dividing up the ribs or knives of the rotor or the stator structure-in the said mill into a number of groups, where these groups individually by means of suitable arrangements have been adapted to slide within certain limits in the axialdirection of themachine, at the same time as the groups are subjected to spring pressure which may be adjusted from the outside of the machine and which thus may be used to determine the pressure with which a certain group of ribs is supposed to rest against the correspondingribs on the other part of the machine.

According to this invention, this arrangement is further constructed in such a way that the means arranged for adjusting the ribs groupwise 'may be formed as pipes, arranged inside each other-for separate groups in such a way that the number of groups in the machine which may be This will thus have the action arranged for individual adjustment and spring action can be made quite great. The adjustment of the tension or pressure of the spring which is adapted to work on these groups may be arranged in such a way that a certain number of groups by means of one individual adjusting mechanism can be given a certain definite spring pressure suitable for the purpose.

It is evident that this arrangement of groupwise adjustable ribs may be used as a substitute for the individual spring mechanisms between each rib, the said springs then being replaced by suitable distance pieces. At the same time it is evident that such individual springs between each two ribs may be maintained, and both the groupwise action and the individual action will then be present in the mill.

In order that the invention may be easily understood, it will in the following be described with reference to the drawings which diagrammatically illustrate one embodiment of the mill, for instance that type which has been described in the above mentioned patent.

In the drawings,

Fig. 1 illustrates a fractional longitudinal cross section of the mill at the line I-I of Fig. 4.

Fig. 2 is a cross section at the line IIII of Fig. 1, and

Fig. 3 is a cross section at the line III-III of Fig. 1.

Fig. 4 is a cross section through the machine according to the invention and Fig. 5 illustrates a part of one of the elements, rotor or stator, diagrammatically rolled out in a plane.

Fig. 6 is a substantially longitudinal sectional View through an embodiment of the invention along line VIVI of Fig. 4, the teeth on the upper part of the stator being omitted for the sake of simplicity.

The machine according to the embodiment of the invention shown in Fig. 4 comprises a frame or stator structure I with channels I! for cooling liquid. In the frame which on the inside has substantially cylinder-form, a rotor element I8 is journalled on a shaft I9, a number of ribs or teeth, as shown in Fig. 6, being mounted on the rotor at a distance from each other and dimensioned in such a way that the diameter of the rotor plus the extending ribs together will substantially correspond to the inside diameter of the frame or stator structure. In the stator structure I, Figs. 1, 2 and 3, a number of ribs 2 is arranged. These ribs are provided with dovetailed downwardly extending elongations 3 which are adapted to be received in suitably shaped corresponding dovetailed grooves in the frame I in such a way that the ribs 2 will be able to move in the axial'direction of the machine.

Between the individual ribs 2, in the embodiment shown in the drawings, coil springs 4 are arranged which exert a pressure on the ribs so as to yieldably hold the same at suitable spaced distances from each other. In order to prevent the material from the mill passing into the space Where these springs are located, the ribs may be provided with aprons I5, covering the space between the ribs. However, these aprons must not be large enough to prevent the axial movement of the ribs within the desired limits.

According to the invention, the ribs may now, as another embodiment or in combination with the construction above mentioned as shown in Fig. 1, be divided into groups, for instance of three ribs, each of these groups being subjected to the action of a member, for instance the pipe 5 and a rod 6, sliding one inside the other, and which at one end is provided with flanges 'I and 8, resting against the outside of the first rib in each group, respectively, while the last rib of each group is rigid with the corresponding inner member, viz. the pipe 5 and the rod 6, repectively. The pipe 5 and the rod 6 are passed outside the frame of the machine and are on the outside arranged in such a way that they will be under the action of coil springs 9 and III which respectively through the pipe 5 and the rod 6 will subject the respective groups or ribs to a suitable pressure in the axial direction. This pressure may be varied by suitable tightening of the springs 9 and III, for instance by arrangingas shown in Fig. 2-a ring II which will rest against a number of springs III, which again are positioned around the periphery of the machine, and furthermore by means of a ring nut I2 which is threaded into an extending part I3 on the frame of the machine; By tightening the ring nut I2, the ring II will thus compress the spring I0, and the corresponding action can be obtained by means of the ring nut I2 as shown in connection with the ring II and the coil spring 9.

The means illustrated for adjusting the spring pressure on the group of ribs 2 may naturally be substituted by other mechanical means, for instance by lever systems which are introduced directly to the group through the frame of the machine. In the same way it is possible in this construction for a certain use to omit the springs 4, substituting for these compact distance pieces, the spring action then being taken entirely over by the springs 9 and III etc.

In Fig. 5 the arrangement of the ribs on the rotor or the stator part is diagrammatically illustrated on a flattened out plane. arranged in parallel side by side and groupwise, staggered in relation to each other in such a way that a zig-zag path is formed as indicated by the arrow between one group of ribs and the adjacent group of ribs. This arrangement is of importance due to the fact that in this way one will prevent any direct passage in the axial direction of the machine, through which material may be allowed to pass without coming into contact with the ribs. Fig. 4, it will be seen that the individual groups of two and some of three ribs are staggered in relation toeach other. The number of ribs in each group may evidently be varied according to wish. It is furthermore characteristic that the ribs which in one group are pointing ahead, are mounted so far ahead that the front end will extend beyond the rear end of the retracted group of teeth of the next preceding group of teeth.

I claim:

A grinding device, comprising a stator incorporating a hollow drum having a substantially cylindrical inner surface and radially inwardly projecting rib-like teeth, a rotor consisting of a cylindrical body journalled for rotation within said stator and including outwardly projecting rib-like teeth adapted to cooperate with said teeth on the stator to produce a grinding action, the teeth of the stator being axially shiftable relative to the latter substantially independently from each other said teeth being subdivided into a plurality of axial groups each comprising at least two adjacent teeth, a sleeve-like bolting member for one of said groups extending axially through said group to a point outside of the These ribs are In the embodiment shown in stator, said member being rigid with one tooth of said group and projecting freely through the remaining teeth thereof axially biased resilient means to yieldably secure said sleeve-like bolting member to said stator, a bolt of smaller diameter than said sleeve-like bolting member extending axially through said second group, said bolt being rigid with one tooth of said second group 

